After killing two co-workers, businessman Jeffrey flees with his two young daughters, Victoria an Lilly. But he's driving recklessly and the car spins out in the icy road and over a cliff to the woods below. They walk and come to an old looking cabin. He's wounded and realizes there's no hope--and just as he's about to shoot one of his daughters in the head something dark and malevolent appears and snatches him away.

Five years later, Jeffrey's identical twin, Lucas (Nikolaj Coster-Waldau of Game of Thrones) is still searching for his nieces. Someone finds them in that same cabin--but they seem little more than feral children. They are taken to a hospital. Victoria seems to recover quickly and be "normal", but the other sister was only a year old and can barely speak. The doctor tells Lucas that the girls had created an imaginary friend, "Mama", who cared for him. Little does he realize that this entity is real--and has returned with them. The doctor wants to study the girls and sets Lucas and his punk-rock girlfriend, Annabel (Jessica Chastain) in a house. Lucas is almost killed by Mama and is sent to the hospital, leaving Annabel alone with the girls--and the monster. But what is she? The doctor begins to have an idea and it doesn't end well for him...

MAMA would have been a perfect horror movie if not for a few scenes with awkward dialogue and unlikely motivations for the characters. However, it has an interesting story, is creepier than the new EVIL DEAD movie, and is one of the best horror films so far this year.